1. Technical Field
The present invention relates to a method of forming a film pattern, an active matrix substrate, an electro-optic device, and an electronic apparatus.
2. Related Art
A semiconductor device composed of a circuit wiring formed of a conductor thin film (film pattern) disposed therein, a thin film such as an insulating film covering the circuit wiring, and a thin film made of semiconductor all stacked on a substrate has been known from the past. As an efficient method of forming a thin film in such a semiconductor device, a droplet ejection method (inkjet method), in which droplets of a functional liquid containing a thin film material or the like as dispersoid is ejected from a droplet ejection head, and the landed functional liquid is dried to remove the dispersion medium thereby forming the thin film, is known to the public (see, for example, JP-A-11-274671).
In forming a film pattern by the droplet ejection method, banks for partitioning the pattern forming areas are formed, and the functional liquid is ejected towards the pattern forming areas partitioned with the banks and having recessed shapes. And, the film pattern is formed after drying the functional liquid ejected to the pattern forming areas.
In recent years, source wiring (film pattern) and gate wiring (film pattern) both electrically connected to a plurality of thin film transistors provided to an active matrix substrate are formed using the droplet ejection method described above.
The active matrix substrate is provided with the source wiring and gate wiring, which are electrically connected to each of the thin film transistors, disposed on the substrate in a lattice manner with each other, and typically has a structure in which the source wiring and the gate wiring are formed on different surfaces via an interlayer insulating film or the like.
And, since the source wiring and the gate wiring are made of metal materials, leak current might be caused by diffusion of metallic ions, which might prevent the transistor from operating preferably. Therefore, in some technologies, the diffusion of the metallic ions described above is prevented by stacking a cap layer, which is composed of Ni or the like having lower conductivity than the metal materials forming the source wiring and the gate wiring, on each wiring.
Incidentally, an active matrix substrate, which can be formed with a simplified wiring forming process of forming the gate wiring and the source wiring on the same surface in the same manufacturing process, can also be considered in contrast with the active matrix substrate having the gate wiring and the source wiring formed via the interlayer insulating film as the stacked structure. In this active matrix substrate, for example, the source wiring is formed so as to be divided by the gate wiring in intersections between the gate wiring and the source wiring. Further, the active matrix substrate is provided with conductive sections (conductive films) for connecting the source wiring thus divided.
Still further, an active matrix substrate, which is provided with the cap layer for preventing the diffusion of the metallic ions described above and has a structure of divided source wiring (film pattern), can also be considered.
However, if the cap layer is disposed on the gate wiring and the source wiring divided by the gate wiring, which are formed in the wiring forming areas (pattern forming areas) partitioned with the banks, using the droplet ejection method, the material forming the cap layer wets and extends on the wiring forming areas to form the cap layer covering the entire surface of the gate wiring and the source wiring. Note here that, as described above, the conductivity of the cap layer is lower than those of the metal materials forming the gate wiring and the source wiring. Therefore, in order for providing preferable electrical connection to the divided source wiring, it is necessary to remove the cap layer covering the source wiring to degrade the conductivity for connecting the divided source wiring by forming the conductive sections directly on the source wiring thus exposed.
However, if the process of removing the cap layer is required, as described above, in forming the conductive sections connecting between the divided pieces of the source wiring, it becomes difficult to simplify the process of forming the source wiring, thus contributing to preventing enhancement of productivity.